Variable volume chamber



G. H. Roussel. 2,688,150

VARIABLE VOLUME CHAMBER 2 Sheets-Sheet 1 Sept. 7, 1954 Fiiled Aug. 6, 1947 GEORGES u. RIJVsET ILlllll/l/ll/ /l/// ATTORNEY Sept. 7, 1954 Q H, ROUSSEL 2,688,150

VARIABLE VOLUME CHAMBER Filed Aug. e, 1947 2 sheets-sheet 2 INVENTOR `N N @forests nioussn.

ATTORNEY Patented Sept. 7, V1954 s PATENT oFFlcE VARIABLE VOLUME CHAMBER4 Georges Henri Roussel, Courbevoie, France Application August 6, 1947, Serial No. 766,56 In France May 27, 1946 Y 'section 1, Public Law 69o, August s, 1946 Patent expires May 27, 1966 My invention has forits object damping systems and more generally any variable volume systems such as pumps, atomizers and the like including, inside a rigid casing, a yielding sealed chamber or bladder containing a vfluid and adapted to be submitted to variations in pressure and in volume through deformation. In such devices, a piston is adapted to act on a portion of the wall ofthe bladder, the diameter of the piston Abeing selected in a manner such that it may move with sufcient playv for .allowing the penetration of the 'deformed parts inside thev Another object contemplates means for per- 4 Claims. (Cl. Iii-52) mitting the free sliding movement of elastic packing means on the inside surface of the bladder. This isobtained Vby choosing the materials in contact so that the friction co-efcient of the outside surface of the bladder, when dry, upon the inside surface of the rigid metallic chamber, or cylinder, be superior to the friction co-ecient .of the elastic means upon the inside surface of `4the bladder. Thereby is prevented the formation of folds or creases that may cause tears of the bladder during the sliding motion of contacting surfaces.

As an example, and for purposes of illustration only, an embodiment of the invention is shown inthe annexed drawings, wherein: Fig. 1 is alongitudinal section through a pressure chamber showing the `basic principles of theinvention;

Fig. 2 vis a modification of 'the lower part of Fig. 1.

Fig.3 is a longitudinalsection of a door closing appliance associated with a hydraulic damper according to the invention. e

Fig. 4 is a longitudinal section vthrough a doorclosing mechanism according to the invention.

Fig-5 is an enlarged detail-section showing the elastic Apacking means,.Fig. Gis a similar view showing a'modiflcation of said means.

Fig. 'Tis 1a 'schematic view of a door vclosing device'according to the invention and having articulated arms.

Referring to the drawings, lwherein the same reference characters vrepresent corresponding parts throughout, the rigid member of Fig. 1 is formed of a tube or'cylinder 4 one extremity or end of which is closed and the other end closed by the bottom of a chamber 2 in which the fluid used in the device can penetrate through one or more apertures 3. This chamber 2 is closed by a cover at each end, the cover opposed to that provided with the aperture 3 being solid. Inf side the cylinder there is disposed a flexible enclosure or bladder l formed of rubber, for example, which is closed towards the open end of the cylinder and having its open end directed towards the closed end of said cylinder. The open end of the bladder is clamped kbetween cooperating corrugations on the'projecting bottom of the chamber 2 and on the inside of the cylinder 4. The bottom of the bladder l rests on the rounded extremity of a plunger 5 projecting from the center of the outside cylinder bottom. The diameter of the plunger or piston is slightly inferior to the inside diameter of the tube in order to leave a space suflicient for the formation of the bladder fold, as is to be explained later on.

The inside surface of the deformed part of the bladder is capped by a rigid washer 6 upon which a diaphragm l is disposed, the edge of this diaphragm being in contact with the wall of the bladder. The said bladder is adapted to hold a fluid or liquid, for example oil, which penetrates more or less into the apertures 3 inside the chamber 2 and, by doing so, compressing the air contained in said chamber according to the pressure exerted upon the bladder by the piston 5. The flexible diaphragm being in contact with therigid washer transmits thereto the fluid pressure and, accordingly, protects the bladder fold against the pressure stresses, while the diaphragm 'l prevents the .passage of huid inside the so formed folds. Whenever the piston 51s withdrawn, the diaphragm is adapted to be deformed away from the bladder, that is: the edges of said diaphragm are withdrawn'from the inside surface of the bladder thereby allowing the possible liquid leaks inside the fold to flow back inside the bladder.

In the modification illustrated in Fig. 2, there is inserted a stationary sleeve 8 inside the cylinder 4 between the latter and the-bladder in order to protect the said bladder against the frictional contact of the sliding cylinder 4.

In order that the device of the invention may operate properly, as basically described above, it is important 'that the inside ,surfacek of the bladder be lubricated: consequently, the fluid used must either have lubricating properties or 3 a lubricant introduced therein. Since the outer surface of the bladder remains dry and the different surfaces considered operate frictionally during operation, it is imperative that thev various friction co-eicients be properly chosen so that the sliding of the diaphragm inside the bladder be possible without causing creases in said bladder. This is perfectly possible if the friction coefcient of the bladder, dry, upon the inside surface of the tube (0.6) is above the friction co-efiicient of the diaphragm upon the wet inside surface of the bladder (0.15).

In Fig. 3 which is an axial cross-section of a door closing system with a hydraulic damper, two rubber bags or bladders Ia and IbI of annular cross-section are secured to either side of a sleeve 9 and are housed inside cylindrical casings I and II which are rigid with said sleeve. The axial passage-way round which the said bladders are located forms a central passage defined by the tubes I2 and I3 also secured to the sleeve 9. A rod I4 adapted to slide inside said tubes I2 and I3 carries two annular oppositely directed pistons I5 and I6 acting respectively on the bottom portions of the bags I a and Ib. Said pistons I5 and I6 are designed in the same manner as the piston 5 of Fig. 1 and 2, so as to show inside the casings IIJ and II and with reference to the tubes I2 and I3 a certain play whereby the deformed portions of the bladders may engage freely the clearance thus formed between the pistons and said casings and tubes.

A spring I1 bearing against the bottom of the casing I0 acts on the piston I5; said spring may obviously be done away with and replaced by the pressure of a mass of compressed air acting on said piston. The folds formed by the bladders are capped by a corresponding rigid washer 6 carrying an annular diaphragm I8 similar to the diaphragm 1 of Figs. 1 and 2. The two blad ders Ia and Ib communicate with each other on one hand through a channel I9 formed in the sleeve 9 and provided with an adjusting needle valve 20 and, on the other hand, through a channel 2l also formed in the sleeve 9 and controlled by a ball 22 forming a valve adapted to open the passage from Ib to Ia..

For a certain displacement of the rod I4 carrying the pistons, the reduction in volume shown by one of the bags corresponds to an equal increase in volume of the other bag. In the direction of opening of the door, the rod I4 enters the cylinders I0 and II against the action of the spring I1 while liquid passes through the channel 2l after removing the ball 22 off its seat. The automatic closing of the door is ensured through the expansion of the spring I1 that urges the rod I4 forwards. The movement of the latter is braked through the fact that the liquid can no longer find a return passage otherwise than through thethrottled channel i9.

According to Fig. 4, wherein an embodiment of the invention is shown in the form of a door closing device, said device consists in a tubular` casing 23 rotatably secured by means of a pin 24 to a support 25 attached to a door (not shown). Inside the casing are disposed two pistons 2G and 21 secured to said casing and a central circular ring 28 dividing the casing into two chambers each housing a damping arrangement, said damping arrangements acting for vopposite directions. On each side of the ring and secured thereto by crimping inside notches 3l are mounted two tubes 32 forming rigid chambers 4 30 connected by reinforcing heels to the central ring 28.

The left tube 32 is disposed inside a sleeve 33 having acircular centering shoulder 34 bearing against the casing 23. Opposite the inner ends of each of the pistons 26 and 21 and seated against the bottom of each bladder, diaphragme 35 are provided to protect the folds of the bladder which, according to the preceding explanation, are formed when the piston penetrates inside the bladder. A spacing rod 36 maintains the diaphragms 35 in properly spaced arrangement while a bore 29 inside the ring 28 placesboth bladders in mutual communication.

From the foregoing description, the general operationofrthe device should be readily understood: more specifically, the device of Fig. 4 consists essentially of a fixed casing inside which the two opposed damping mechanisms are relatively displaced axially. For this displacement, and to permit connection of an outside member, an extension bushing 2l is provided on the ring 28 projecting outside the casing through a longitudinal slot 29. For adjusting the flow of iluid transferred from one bladder to another, through the communicating bore 29, a needle valve I9 is provided to obstruct said `bore more or less and actuated by the operating screw I8. Consequently, connection with the bushing 2|, for operating the inside cylinder arrangement may be effectuated by means of a bracket I1 engaging the bushing 2I (see Fig. 4:).v

As shown in Fig. '7, the centre ring 2B and the pivots providing the rotational axis 4I are mounted on the brackets I1` and 25 integral with a plate 42 which is adapted to be secured to a door (not shown). A bell crank 45 is adapted to pivot around the axis 4I and, also, is pivotally connected at 24 to one end. of the casing 23; the free extremity of said crank 45 is connected at 44 to an adjustable arm 46 the other end of which is connected to a wall bracket 43 which may be secured to the jamb of the door.

Whenever the door is opened, the plate 42 moves therewithv and the device describes an arc of a circle around the axis 4I while the axis 24 is also arcuately displaced to move therewith the casing 23 and, of course, the two pistons 26 and 21. The casing is displaced with respect tothe centre ring 28 whereby this movement moves the rigid chamber and bladder with respect to the piston. Having a certain displacement, the decrease in volume of one bladder corresponds to anequal increase of volume of the other bladder. During its movement,.the centre ring 28 compresses the spring 41 whereby the fluid expelled from one bladder passes through the bore 29,` the return movement being effectuated by the vmotion of the spring, said return movement being further braked by the second damping device.

As shown in the drawings, the rigid chamber and bladder as well as the center `ring are sup-` ported inside a sleeve sliding within the tubular casing, this arrangement enabling easy servicing in the eld and replacement of the defective units by a new one.' l The arrangement of the casing inside enables also the liquid to be caught inside the casing inthe event of a bladder rupture; for an apparatus of this type this is an important advantage.

The showing of'` Fig. 5 discloses a diaphragm of a slightly modied character` constituted by a rigid washer 31 the diameter of which is `slightly less than that of the bladder. YAn elastic packing 40, of annular formation, is disposed againstthe Washer and a cup 39 marginally apertured maintains the packing in place against the washer. The apertures of the cup are provided to permit the return of liquid leaks inside the bladder.

Another modication is shown in Fig. 6 wherein the rigid washer 3l is formed with a central conical shoulder whereby, in one direction of movement, the annular elastic packing 40 has a tendency to be squeezed against the surface, to increase its packing effect. In the opposed direction, the friction against the surface of the bladder and cone allow disengagement of the packing to permit the return of leaks in the bladder through the apertures of the cup.

It must be understood that various changes as to the shape, size and arrangement of parts can be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

What I claim is:

1. Variable volume chamber of the character described, comprising a tubular enclosure, a flexible bladder lining the inside of said enclosure and closed at one end, a plunger adapted to deform the closed end of the bladder by penetration therein, said plunger being of smaller diameter than the inside diameter of the bladder for allowing a bladder fold to be formed therebetween, and a flexible diaphragm inside the bladder opposite the plunger and held thereagainst to form a piston bearing on the inside surface of said bladder.

2. In a variable volume chamber, a tubular casing, an elastic bladder lining the inside of the casing and closed at one end, a plunger adapted to deform the closed end of the said bladder by axial penetration therein, said plunger being smaller than the casing to allow the formation of a bladder fold therebetween, and a flexible diaphragm inside the bladder opposite the plunger and held thereagainst for pressing the bladder against the casing ahead Aof the fold.

3. In a variable volume chamber, a cylindrical casing, a plunger co-axially movable in said casing and concentrically spaced therefrom, an elastic deformable bladder closed at one end and inserted with its closed end towards the plunger and in Contact with the inside wall of the casing, whereby the plunger is adapted to deform the bladder by axial penetration therein, said plunger being of smaller diameter than the inside diameter of the bladder for allowing a bladder fold to be formed therebetween, and a flexible diaphragm at the closed end of the bladder slidable thereinside as the plunger deforms the bladder and held against the plunger to form a piston to keep said bladder pressed against the wall of the casing.

4. A door-closing mechanism, comprising a tubular casing, a ring slidable inside said casing, means outside said casing for imparting a longitudinal movement to the ring through the casing, an open-ended cylinder on each side of the ring in axial alignment with the opposite cylinder, a closed elastic bladder in each cylinder, means for affording communication between the bladders through the ring, a plunger at each end of the casing adapted to enter the corresponding cylinder and deform the bladder therein as the ring is moved relatively to the casing, means in each bladder immediately adjacent the plunger for pressing said bladder against the cylinder wall, and a spring inside the casing and adapted to urge the cylinder assemblies towards one end of the casing.

References Cited in the le of this patent UNITED STATES PATENTS Number 

